Objective

2

To investigate whether Jiedu Huoxue prescription can induce macrophage autophagy and inhibit inflammatory response to stabilize vulnerable plaques of atherosclerosis （AS） by regulating phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt）/mammalian target of rapamycin （mTOR） signaling pathway.

Method

2

Thirty ApoE

-/-

mice fed with high-fat diet were randomly assigned into model， low-， medium-， and high-dose （5.35， 10.7， and 21.4 g·kg

-1

·d

-1

， respectively） Jiedu Huoxue prescription （Chinese medicine）， and rapamycin （2 mg·kg

-1

·d

-1

） groups. Six ApoE

-/-

mice fed with common diet were used as the control group， and 6 C57BL/6J mice fed with common diet as the blank group. The drugs or equal volume of normal saline were administrated by gavage after 7 weeks of modeling， and the treatment lasted for 4 weeks. The serum levels of lipids and inflammatory cytokines ［monocyte chemoattractant protein-1 （MCP-1） and interleukin-6 （IL-6）］ were measured. Hematoxylin-eosin （HE） staining was employed to observe the pathological changes of the vascular wall of the aortic root. Immunohistochemistry was employed to detect the expression of macrophages/monocytes monoclonal antibody （MOMA-2） and

α

-smooth muscle actin （

α

-SMA）. Transmission electron microscopy was employed to count the autophagosomes in the aorta， and Western blot to determine the protein levels of Beclin-1， LC3， PI3K， Akt， and mTOR.

Result

2

Compared with the control group， the model group showed elevated serum levels of lipids， MCP-1， and IL-6 （

P

<

0.05）， inhibited expression of MOMA-2 and

α

-SMA （

P<

0.05，

P<

0.01）， up-regulated protein level of Beclin-1 （

P

<

0.05）， and down-regulated protein levels of PI3K， Akt， and mTOR （

P

<

0.05，

P<

0.01）. The model group presented obvious atherosclerotic plaques on the inner wall of the aorta， infiltration of inflammatory cells in the plaque， thickened and disarranged vascular intima where the plaque was attached， decreased autophagosomes and mitochondria， and destroyed mitochondrial structure. Chinese medicine and rapamycin groups showed lower levels of total cholesterol， triglycerides， low-density lipoprotein cholesterol， MCP-1， and IL-6 （

P

<

0.05）， higher level of high-density lipoprotein cholesterol （

P

<

0.05）， inhibited expression of MOMA-2 and

α

-SMA （

P

<

0.05，

P<

0.01）， higher protein levels of Beclin-1 and LC3Ⅱ （

P

<

0.05，

P<

0.01）， and lower protein levels of PI3K， Akt， and mTOR （

P

<

0.05，

P<

0.01） than the model group. Moreover， Chinese medicine and rapamycin groups showed only a small number of atherosclerotic plaques on the inner wall of the aorta， reduced infiltration of inflammatory cells and thickness of the blood vessel wall， and increased autophagosomes and autophagic lysosomes.

Conclusion

2

Jiedu Huoxue prescription can improve lipid metabolism， enhance macrophage autophagy， and reduce AS-induced inflammation to improve the stability of vulnerable plaques in AS mice by inhibiting the PI3K/Akt/mTOR signaling pathway.